Help! Starter not cranking

[austinado16]

1990 'burb w/ 5.7L and 4L60. Always 100% reliable and has never left me stranded.

Fired it up tonight and drove 2 miles to the store. Shut it off for about 5min and then attempted to start it and drive away. No starter action at all. Not a click, nothing. I had my daughter bring over a digital voltage meter. I have 12v at the large terminal on the starter. I'm not getting 12v at the small terminal at the starter, that the gray wire goes to. I tried jumping from the large terminal to the small terminal, and still get no starter action.

I then tested for voltage at the electrical connector on the driver's side of the transmission. There are 3 wires going into that connector. 2 of them get 12v from the key, when the key is in the start mode. The 3rd wire has nothing, so I tried jumping from one of the 2 key powered wires, but still got no starter action.

I'm quite screw at the moment, not only because I can't get the truck started, but because my daughter and I were leaving tomorrow to go camping for the weekend.

Ignition switch is maybe 2 years old. Starter is from NAPA and maybe 10yrs old, but since we don't drive the 'burb often, doesn't have very many miles on it. Battery is a year old and showing 12.5v. Grounds between engine, battery, and frame are all good.....tested tonight w/ an ohm meter.

Any help greatly appreciated!

 

[Eighty5C10]

1990 'burb w/ 5.7L and 4L60. Always 100% reliable and has never left me stranded.

Fired it up tonight and drove 2 miles to the store. Shut it off for about 5min and then attempted to start it and drive away. No starter action at all. Not a click, nothing. I had my daughter bring over a digital voltage meter. I have 12v at the large terminal on the starter. I'm not getting 12v at the small terminal at the starter, that the gray wire goes to. I tried jumping from the large terminal to the small terminal, and still get no starter action.

I then tested for voltage at the electrical connector on the driver's side of the transmission. There are 3 wires going into that connector. 2 of them get 12v from the key, when the key is in the start mode. The 3rd wire has nothing, so I tried jumping from one of the 2 key powered wires, but still got no starter action.

I'm quite screw at the moment, not only because I can't get the truck started, but because my daughter and I were leaving tomorrow to go camping for the weekend.

Ignition switch is maybe 2 years old. Starter is from NAPA and maybe 10yrs old, but since we don't drive the 'burb often, doesn't have very many miles on it. Battery is a year old and showing 12.5v. Grounds between engine, battery, and frame are all good.....tested tonight w/ an ohm meter.

Any help greatly appreciated!

I have had similar issues in the past with a 94 c3500, the ignition switch on the column went out, may try there. Take it loose, leave it connected to the wiring and use a screw driver to work it. But what confuses me is that you should be able to jump through the solenoid.

 

[austinado16]

Ya, this is pissing me off big-time. Of course it's dark, the truck is in the parking lot of a store, all auto parts stores are closed....and it's been perfect, ever time I've driven it in the last month, just like it always has been.

I find it hard to believe that the starter would suddenly be dead. I can't even jump from the battery powered lug on the starter, to the other big lug, which I would think would at least spin the starter motor w/o engaging the bendix and flywheel?

I think the ignition switch is good...but please correct me if I'm wrong. The a/c compressor clicks on and off when the key is rotated from "on" to "start" positions. Also, the 12v I measured at the switch on the side of the transmission is seeing 12v only when the key is in "start" position. So that makes me think the ignition switch is okay.

I'm assuming power comes from the ignition sw. and goes through the switch on the transmission, and then to the starter?

 

[austinado16]

I'm looking at my factory 1990 Electrical Diagrams and Diagnosis Manual right now. It has a section on page A-36 that troubleshoots the starter. Basically is says if you don't have 12v at the PPL wire on the starter solenoid, then you should check for voltage at BAT-2 and BAT-3 at the ignition switch. If you see voltage at those 2 BAT positions, replace the ign. sw. If you don't see voltage, locate and repair the break in the red wires (2) and the fusible link at the junction block. Is the junction block "C100?" in the diagram? And if so, where is it located.

Also in the diagram, it looks like there's a 3amp "Crank" fuse at the bottom the fuse box. Is that just powering the ECM during cranking to run the fuel pump? Here's the diagram I'm looking at. Maybe this isn't correct for a '90 'burb, and it's for a round nose '90 pickup?

You must be registered for see images attach

 

[Eighty5C10]

I'm looking at my factory 1990 Electrical Diagrams and Diagnosis Manual right now. It has a section on page A-36 that troubleshoots the starter. Basically is says if you don't have 12v at the PPL wire on the starter solenoid, then you should check for voltage at BAT-2 and BAT-3 at the ignition switch. If you see voltage at those 2 BAT positions, replace the ign. sw. If you don't see voltage, locate and repair the break in the red wires (2) and the fusible link at the junction block. Is the junction block "C100?" in the diagram? And if so, where is it located.

Also in the diagram, it looks like there's a 3amp "Crank" fuse at the bottom the fuse box. Is that just powering the ECM during cranking to run the fuel pump? Here's the diagram I'm looking at. Maybe this isn't correct for a '90 'burb, and it's for a round nose '90 pickup?

You must be registered for see images attach

Wiring is my arch enemy and usually I would rather kill it with fire but I firmly believe you are in the right track bud

 

[austinado16]

Anyone know where C100 is located? I don't recall anything like that on my firewall. It would appear that I could test at "6" with the key in "start" mode, and that I should see 12v there during an attempt to start. It also looks like I should be able to jump from "2" to "6" and get the starter to crank......if "2" is getting 12v all the time from the battery via the fusible links.

Guess I can also check for 12v at that "crank" fuse, during a starting attempt.

Anyone know how the transmission park/neutral safety switch comes into play.

 

[austinado16]

It was the starter. Completely dead, even bench testing it.